Reason

Reason: invalid token 'xyz' in CORS header 'Access-Control-Allow-Methods'

What went wrong?

The response to theCORS request that was sent by the server includesanAccess-Control-Allow-Methods header which includes at least oneinvalid method name.

TheAccess-Control-Allow-Methods header is sent by the server to let theclient know whatHTTP request methods itsupports for CORS requests. The header's value is a comma-delineated string of HTTPmethod names, such asGET,POST, orHEAD. If any of the specified values are not recognized by the clientuser agent, this error occurs.

This is a problem that most likely can only be fixed on the server side, by modifyingthe server's configuration to no longer send the invalid or unknown method name with theAccess-Control-Allow-Methods header. It may also be worth checking toensure that the user agent or HTTP library you're using on the client is up-to-date.

See also

• CORS errors
• Glossary:CORS
• CORS introduction
• HTTP request methods